Oscillating pump impeller



Dec. 30, 1947-. J. KUTTNER 2,433,461

OS C ILLAT ING PUMP IMPELLER Filed Aug. 24, 1945 IN VENTOR JUL/U5 KuTrNER ATTORNEY Patented Dec. 30, 1947 OSCILLATING PUMP INIPELLER Julius Kuttner, Beloit, Wis., assignor to Fairbanks, Morse & 00., Chicago, 111., a corporation of Illinois Application August 24, 1945, Serial No. 612,501

1 Claim. 1

This invention relates in general to fluid pumps of oscillating impeller type, and more particularly to an improved impeller for pumps of this character.

The principal object of the present invention is to provide an improved impeller comprised of an integral forged metal vane and shaft structure having radially projecting vanes of generally cantilever character in section, and wherein the completed structure is characterized by minimum weight and low moment of inertia, as well as great strength and high bending resistance substantially uniformly throughout the impeller vanes.

Another object is to provide a forged metal impeller of the foregoing character, wherein is embodied fluid sealing means at the vane peripheries, constituted according to present improvements, by strip elements formed from lightweight material of relatively low density, as aluminum, Micarta, leather or the like, and sealing means along the opposite side margins of the impeller vanes.

Further objects and advantages afiorded by the present improvements, will appear readily from the following description of a preferred embodiment of the invention, and the accompanying drawing thereof, wherein:

Fig. 1 is a transverse sectional elevation of a pump shown somewhat diagrammatically, illustrating the presently improved impeller therein;

Fig. 2 is a longitudinal elevation of the impeller, and

Fig. 3 is an end View of the impeller,

Referring to the drawing by appropriate characters of reference, there is illustrated by Fig. 1 a fluid pump denoted generally by the numeral ID, in which is embodied the improved oscillating impeller I l forming the subject of the present invention. Although the impeller may be employed in pumps serving various purposes, the pump as shown herein, is of a character suitable for use with internal combustion engines to supply scavenging air to the engine cylinders. Since apart from the impeller structure including the axial or shaft portion thereof indicated at I2, the form and structural details of the pump do not concern the present invention, such will be described only briefly.

The pump [9 which is illustrated somewhat diagrammatically, includes a casing structure designated generally by the numeral l4, providing a fluid chamber IS in which the impeller H oscillates. The chamber is divided by casing partitions I6 and fluid seals 1 7 between the partitions and the hub or shaft portion l2 of impeller I l to provide opposite pumping compartments [9 and 20 one for each of the impeller vanes 22. Communicating with the compartment IS on the opposite sides thereof, are passages 23 which serve alternately as inlet and outlet passages for the compartment. Fluid as air, is admitted to the passages 23 on the suction strokes of the vanes 22 in compartment I9, through unidirectional or one-way valves 24 from supply chambers 25 in communication with the atmosphere or other source of air. The air thus drawn into compartment l9 alternately on opposite sides of the vane 22, is discharged therefrom alternately into the passages 23 in response to the compression or discharge strokes of the vane, and thence through similar one-way valves 26 into a chamber 21, from which the air under pressure may be conducted to the engine cylinders. Similar passages 28 are associated with the other pump compartment 20, and include inlet valves 29 and outlet valves 3|] providing respectively, one-way communication between the supply chambers 25 and the passages, and between the passages and a discharge chamber 32 which is similar to the discharge chamber 21.

With reference now to the improved impeller l I (Figs. 2 and 3), the impeller proper is an integral or one-piece structure, formed from a high tensile strength, relatively dense material such as forging steel, and is preferably drop-forged to produce the cylinder-form axial or shaft portion l2, the radially extending diametrically opposed vanes 22, and the opposite shaft projections 33 and 34. As appears clearly from Figs. 2 and 3, formation of the impeller is such that each of the vanes 22 presents opposite planar faces 36 longitudinally of the impeller, with the faces relatively convergent toward the vane periphery 31. Moreover, each vane at its inner or shaft end 38, is symmetrically enlarged or expanded into integral mergence with the shaft portion I 2, with the opposite longitudinal surfaces of the expanded portion presenting concave faces All merging smoothly with the planar faces 36. It thus will appear from the end view of Fig. 3, that each vane 22 is of substantially cantilever form, and the degree of vane taper toward the periphery 31 is predetermined so as to characterize the vane by a sufficiently high bending resistance of uniform value throughout the vane. With high strength forging steel, the vane 22 as thus formed, may be held to a relatively thin or minimum section substantially as indicated in the drawing, while the axial portion 12 may be held to a minimum diameter consistent with the maximum torsional 3 stresses to be encountered in use. Hence, the weight of the impeller is thus at a minimum. Moreover, since the vanes 22 are of relatively thin cantilever form, it will appear that the greater part of the impeller mass is advantageously concentrated near the impeller axis, so that the moment of inertia of the structure is thereby determined at arelatively low value. Consequently, the presently improved impeller characterized by great strength, minimum Weight and low moment of inertia, will improve pump efiiciency and afiord a very material increase in pump output through high speed operation of the impeller, permitted by reason in particular, of the low moment of inertia characteristic of the impeller.

A further feature afiorded by the present improvements, relates to the sealing of the vane peripheries in relation to the pump chamber walls, this being presently effected by substantially L-- shape sealing strips 4!. The strips 4| are formed from light-weight material of relatively low specific gravity, as aluminum, Mi'carta or the like, and are provided in lengths substantially coextensive with the longitudinal extent of the vane periphery 31. In assembly and according to present preference, a pair of the strips are arranged on opposite sides of each vane at the periphery 31 thereof, in the manner illustrated in Fig. 3, and are secured to 'the'va-n'e preferably by a series of equally spaced rivets "42. The paired strips by preference, extend radially :beyond the vane periphery, and each presents a sealing face is of a curvature conforming to the curvature of the pump casing Wall with which the sealing strip coacts (Fig. 1). Since the sealing strips are of low specific gravity or low density material, they will not materially alter the desired low moment of inertia characteristic of the presently improved impeller structure, nor the overall low weight thereof.

In addition to the foregoing, the impeller is provided with a suitable sealing material applied to the opposite end surfaces '45-'01 the vanes 22, the opposite end surfaces 15 of the sealing strips 4|, and the exposed ends 48 of the axial section I 2,

4 in order to effect fluid sealing of the impeller relative to the end walls (not shown) of the pump chamber. As presently preferred, a soft metallic substance such as a suitable solder compound in- 5 dicated at 49, is applied to the surfaces 45, 46

and 48 in a relatively thin coat or layer of uniform thickness.

While but a presently preferred embodiment of the invention is here described and illustrated, it

10 is to be understood that certain modifications may 5 An impeller or the character described, comprising an integral metallic structure formed to provide an axial section, shaft elements extending axially therefrom, and impeller vanes projecting radially from the axial section and each being of substantially cantilever form in transverse section, sealing elements secured along the peripheries of said vanes, said axial section, vanes and sealing elements providing opposite substantially co-terminal end surfaces, and sealing means 25 for each of said end surfaces comprising a layer of a relatively soft metallic material bonded to the end surface.

JULIUS KUT'INER.

30 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS- 

